Based on the observation that some of the premature aging diseases have
defects in DNA repair, it was hypothesized that the longevity of animal species
is determined by the species-specific rate of DNA repair. Species that had
a high rate of DNA repair were expected to have a long lifespan. Species with
low rates of DNA repair would be short lived. Though some data supported
this hypothesis, a reanalysis of the data found little evidence to favor earlier
conclusions[23].

In 2009, Walker and coworkers reported a case study of a sui generis condition
observed in a 16-year-old girl who had the appearance and anthropometric
traits of an 11-month infant [24]. External and internal organs were infantile,
including brain structure. After fetal development and birth, she had failed to
mature into early childhood or adolescence. In a sense, her condition is the
opposite of the premature aging conditions. The extreme rarity of this condition
(i.e., more rare than the very rare monogenic disorders that produce premature
aging) suggests that a simple loss of function in a single gene is unlikely to be
at fault. This strange and sad case raises many questions about human development
and aging, but, at this time, there are no answers.

Though aging is a naturally occurring process, it is also a disease. It is a true
disease, like any other disease, because it causes the decline of function in various
organs; it leads to frailty and a reduced ability to cope with physiological
stressors; and it leads inevitably to death. A disease that causes premature aging
is a disease that produces all of the aforementioned features at an early age.
When we examine diseases of premature aging, we find that the underlying
mechanisms of these diseases are manifold: chromatin instability (Hutchinson–
Gilford progeria); DNA instability (Werner syndrome); accumulation of toxic
cellular products (tauopathies and prion diseases); mitochondrial degeneration
(Wolfram syndrome); telomere shortening (dyskeratosis congenita).

What do
all these syndromes of diverse etiology have in common? The answer to this
question is the topic of the final sections of Chapter 4, from which excerpts
will be selected for later blogs.

Perl Programming Language

Ruby Programming Language

Methods in Medical Informatics (Korean)

R for Medicine and Biology

About Me

Jules Berman received two baccalaureate degrees from MIT; in Mathematics, and in Earth and Planetary Sciences. He received the Ph.D. from Temple University, and the M.D. from the U. of Miami. He received post-doctoral training at NIH and residency training at Geo. Washington U Med Ctr. He is board certified in anatomic pathology and in cytopathology. He served as Chief of Anatomic Pathology, Surgical Pathology and Cytopathology at the Veterans Administration Medical Center in Baltimore, Maryland, where he held joint appointments at the University of Maryland Medical Center and the Johns Hopkins Medical Institutions. In 1998, he became a Medical Officer at the U.S. National Cancer Institute and served as the Program Director for Pathology Informatics in the Institute's Cancer Diagnosis Program. In 2006, Jules Berman was President of the Association for Pathology Informatics. In 2011 he received the Lifetime Achievement Award from the Association for Pathology Informatics. Today, Jules Berman is a free-lance writer. He has first-authored more than 100 articles and 13 book titles in science and medicine.